How to make two Retrofit calls in chain with RxJava?

[Avante]

I make a call to recover some data and the second call - which should be made inside the first - uses one of the fields of the previous call.

val restApi = retrofit.create(RestAPI::class.java)
testAPI.searchDoc("language", "title_query")
        .subscribeOn(Schedulers.io())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe { p0 ->
             /** É aqui onde eu quero recuperar os dados de p0 e com eles fazer 
                 a segunda chamada. **/
            }
        }

How do I use one of the first call fields to do the second? I'm using Kotlin and working with RxJava.

Question summarized: How do I use the recovered data in the first call to make the second one inside the RxAndroid?

[chanisef]

I believe that in your case it is better to do within chain, not subscribe. Use the operator http://reactivex.io/documentation/operators/flatmap.html :

val restApi = retrofit.create(RestAPI::class.java)
restApi.searchDoc("language", "title_query")
    .flatMap { restApi.doSomethingWithDoc(it.field) }
    .subscribeOn(Schedulers.io())
    .observeOn(AndroidSchedulers.mainThread())
    .subscribe { p0 ->
}

If you need the original value, you can use the mapping function and return a Pair (or anything else):

restApi.searchDoc("language", "title_query")

.flatMap({ restApi.doSomethingWithDoc(it.field) }, { doc, smt -> Pair(doc, smt) }, false)

.subscribe { pair ->

}